Request to help Hillsborough River with water pumped from sinkhole raises concerns

TAMPA — On this everyone seems to agree: It's good to make sure there's enough water flowing in the Hillsborough River to keep it from becoming so salty that it stresses fish and other wildlife.

But how to do that?

That's been a point of disagreement in the past, and is so again.

The Southwest Florida Water Management District, or Swiftmud, is asking the state for permission to pump up to 3.9 million gallons of water per day from a sinkhole known as the Morris Bridge Sink. The sinkhole is in northeast Hillsborough County in the Lower Hillsborough Wilderness Preserve.

If the Florida Department of Environmental Protection approves, that water would be used to boost the flow of the river during dry periods. In the past, the river flowed with enough volume to keep saltier water from Tampa Bay from coming upstream, but that changed after the city built a dam at Rowlett Park to create a reservoir in 1897.

After decades of dwindling river flows, local and state officials came up with a strategy in 2007 to boost the flow of the river. It calls for first using water from Sulphur Springs and from a complex of sinkholes known as the Blue Sink, then, as necessary, from the Tampa Bypass Canal and the Morris Bridge Sink.

Swiftmud officials say the average amount pumped from the Morris Bridge Sink would be about 2 million gallons a day over the course of a year. But it would vary, based on the need.

"It's important to point out that these quantities may not be needed at all, or they may be needed in different, varying flows," Swiftmud water use permit bureau chief Darrin Herbst said at a public hearing on the project last week. And, the agency says, groundwater modeling shows the pumping won't significantly impact other resources in the area.

But groups such as the nonprofit Friends of the River, the Sierra Club and the city of Temple Terrace oppose Swiftmud's idea, saying pumping out the Morris Bridge Sink could dry up nearby homeowners' wells and wetlands in the 16,000-acre preserve.

"It's a special place," Tampa Bay Sierra Club chairman Kent Bailey said. "We really want to see it retain its natural characteristics and not be disrupted."

This is not the first time this sort of policy discussion has taken place.

Two years ago, the pumping request was for Blue Sink, a complex of Sulphur Springs-area sinkholes in the city of Tampa. Residents of neighborhoods like North Forest Hills worried that the pumping would affect their lakes, but officials said they expected any effects from pumping to be minimal.

State regulators approved the request and now the city of Tampa — a partner for Swiftmud at Blue Sink, though not at Morris Bridge Sink — has launched $2.5 million in construction that is scheduled to be completed in August.

Near the Morris Bridge Sink, some neighbors are skeptical.

"I just can't believe this could really be approved," said Chet Joyner, 76, whose Thonotosassa home backs up to the preserve. In 2000, he said his well had to be replaced after emergency pumping from the Morris Bridge Sink during a severe drought.

Joyner wasn't alone. Tampa Bay Water replaced 13 residential wells that failed after it pumped 6.7 million gallons of water per day from the sink.

"Our main concern today would be, at a minimum, looking for very strong conditions to protect the wetlands in and around the sink as a result of the withdrawals in this permit application," said Hillsborough County Environmental Protection Commission general counsel Rick Tschantz. There's an annual report required, but he said there should be a trigger established so pumping would stop if it was obviously hurting the sink.

Opponents also argue that it would be smarter to pump more water from the Tampa Bypass Canal than to put a new pump into the Morris Bridge Sink.

Former Swiftmud environmental scientist Sid Flannery, who retired last year, spent 30 years with the agency, much of it studying minimum flows and part of it considering the potential for pumping water from the Morris Bridge Sink. He said he concluded that the recovery strategy adopted in 2007 should be re-evaluated with more emphasis on the bypass canal and less on the sinkholes.

When it created the bypass canal to help with flood control in the late 1970s and early 1980s, the Army Corps of Engineers dug into the top of the Upper Floridan Aquifer, Flannery said. As a result, the bypass canal already discharges significant amounts of fresh water, by one estimate up to 20 million gallons a day.

With the availability of more water from the bypass canal, he said, it doesn't make sense to risk harming the Morris Bridge Sink or surrounding wetlands, which "are part of the best wildlife corridors we have left in west-central Florida."